March 2010 FASTflo WHC56 Service Manual Working towards a cleaner future
March 2010 WHC56 Service Manual • • • This manual must be read by Service personnel repairing the above appliance models. Take this manual with you when attending Service study meetings. The specifications and contents of this manual may change at any time without prior notification. Never short-circuit any safety devices CONTENTS Overview of Condensing Gas Water Heater ............................................................... 2 Structural Cross-section of Operation Unit ........................
Overview of Condensing Gas Water Heater This water heater is a high efficiency, fully condensing appliance. Unlike a traditional water heater, a condensing type captures heat from the exhaust gas and uses it to preheat the incoming cold water as it passes through the secondary heat exchanger as illustrated below. Conventional type Condensing Gas Water Heater Exhaust About 200°C Exhaust About 50°C Water is heated using the exhaust gas which is about 200°C.
Structural Cross-section of Operation Unit < WHC56, LWHC56> Air inlet Flue collar Secondary heat exchanger Primary heat exchanger Frost sensing switch High-limit switch Drain trap Water level electrode (Front side:No.2) (Back side:No.
Principle of Operation Exhaust High-Limit Switch Frost Sensing Switch Anti-Frost Heater Secondary Heat Exchanger Water Level Electrode 2 Water Level Electrode 1 High-Limit Switch Primary Heat Exchanger Thermal Fuse Igniter Main Flow Control Valve Ignition Electrode Flame Rod Burner Heat Exchanger Thermistor Drain trap SET Bypass Flow Control Valve Primary Gas Solenoid Valve Gas Proportioning Valve Water Inlet Thermistor Gas Solenoid Valve 3 Gas Solenoid Valve 1 Air Supply Gas Solenoid Valve 2 Impe
Explanation of operation 1.Using hot water (1) Turn the ON/OFF button on the remote controller to ON.(The ON/OFF button will turn on the light.) (2) Open the hot water valve to be used. If the water flow sensor detects a water flow above the minimum operation water flow volume, pre-purge(purging gas remaining in the combustion chamber before ignition) will be carried out for a fixed duration of time.
Operation Panel, Remote control Main Remote Controller (RC-7508M) Part number B285 Power On/Off Button / Lamp Display Selection Button Set Button Speaker PLEASE NOTE THAT ONE REMOTE CONTROLLER IS REQUIRED PER INSTALLATION –6–
Initial Operation Before the first use of your water heater, make the following preparations. Follow steps 1 1 through 4. Open the water supply valve. OPEN CLOSED 2 Open a hot water fixture to confirm that water is available, and then close the fixture again. Hot water fixture 3 Open the gas supply valve. 4 Turn on the power.
Setting Hot Water Temperature On this Display 1 Operation Description * The ON/OFF Press the is lit. button ON/OFF to turn it “On”. 2 Use the buttons Here (Eg.: 40°C) WARNING to adjust the temperature. While the shower is being used, no one other than the user should change the temperature, the power switch must not be turned “off”. This is to prevent scalding if the temperature rises.
Approximate hot water conditions 37 38 39 40 41 42 43 44 45 46 47 48 50 55 60 65 70 75 80 Set the maximum temperature to suit your own preference. Washing dishes, etc. Shower, hot water supply, etc. Hot water supply, etc. High temperature • Hot water temperatures are approximations, and may differ from actual temperatures depending on external factors, such as the season and length of piping involved. • When low temperatures are set (for washing dishes, etc.
Sequence Operation Water heating Shutdown p Connect power Fix problem Hot water tap C Bypass flow control valve and main flow control valve move to initial position setting Current leakage safety device normal Disconnect power Water flow senso NO < 2.0 L/mi ON/OFF lamp turns OFF The unit will continue to operature with the code blinking.
Shutdown procedure Hot water tap CLOSED Water flow sensor detects NO < 2.0 L/min. YES Flame lamp goes off Gas proportioning valve closes Primary gas solenoid valve closes Gas solenoid valve 1 closes Gas solenoid valve 2 closes Gas solenoid valve 3 closes Fan motor post purge Main flow control valve opens fully Fan motor stops Has 6min.
– 12 – (VCC) 3 2 1 FM W V V W LS SM LS FROST SENSING SWITCH W BK Y/G B5 W W W W 2 1 2 1 W W EARTH EARTH BR BL BL BL BL 1 1 BL 2 1 EARTH Y/G POWER CORD Y/G 1 2 3 BL BL BK V 8 7 6 5 4 3 2 1 G O R Y BL W BK V W G O R Y BL 8 7 6 5 4 3 2 1 BK W W W G BL 1 2 BK V W G O R Y BL BK V W G O R Y BL 2 1 W W W W W W W W R BL BL BL 4 3 2 1 BL BL BR Y BL R BL BR CURRENT LEAKAGE SAFETY DEVICE (GFCI) BK R W W W W 2 1 BR Y BL R W RC TERMINAL IGNITER IG
Checkpoints and Measures if a Breakdown Occurs Error Codes and Checkpoints Display Description (F) 10 Combustion Abnormality (Joule Drop) (F) 11 Ignition Failure (Initial Flame Fault detection) (F) 12 Flame Rod Does Not Detect Flame (Secondary Flame Fault Detection) (F) 14 Overheat Cutoff Fuse (Thermal Fuse) Triggered Check gas supply piping and pressure. Check for igniter spark. Check gas solenoid valves. Check flame rod.
CN-102 Check the 15V ouput line from the circuit board. Check the 15V ouput line from the circuit board. Check voltage supply from circuit board to remote controller. Check for open or short circuit.
– 16 – Water Inlet Thermistor Abnormality Water Outlet Thermistor Abnormality Heat Exchanger Thermistor Abnormality 31 32 33 Measure the current from the flame rod when there is no flame. Check for a ground fault.
– 17 – Gas Supply Pressure or Manifold Pressure Abnormality Flame Rod Triggered (Doesn't sense flame during operation) Possible Causes Check gas proportioning valve Check gas supply and manifold pressures circuit board Check for a diconnected ground from the Check the current from the flame rod Check the flame rod Checkpoint CN-38 CN-78 Connector No. 2 R-BL Fan Motor abnormality Possible Causes DC0.3 – 15V 4 R-BL 2 CN-38 Check gas proportioning valve.
Main Remote Control (RC-7508M) Power On/Off Button / Lamp Display Selection Button Set Button Speaker Displaying the Maintenance Monitor The Power On/Off Button can be set to either "ON" or "OFF" - unit operation will not be affected by this setting. However, be sure to set the Power On/Off Button to “ON” after turning on the power. 1. Press and hold both the up [ ] and down [ ] selection buttons simultaneously for more than five seconds. 2.
Maintenance Monitor List *2 *1 Data (Display Reading x Multiplier) Minimum Value for Indication Data No. Item 02 2E+ gas judgement result [ab : cd] 03 Total Plug-in Time X 100 hour 100 hours Disp. Range [000] – [1300] 04 Total Combustion Time X1 hour 1 hour Disp. Range [000] – [999] 05 Total Combustion Time X 1000 hour 1000 hours Disp. Range [000] – [1999] 07 Number of Ignition Times X 10 time 10 times Disp.
Circuit Board Replacement * Be sure to read. Reference connection diagram (for simplification, other connections have been omited) It is necessary to transfer data when replacing a circuit board. Vital information about the water heater such as the settings and unit history will have to be transferred to the new board. Please transfer data using the following procedure. If the transfer is not successful, the unit will not operate and a 73 error code will flash on the remote controller.
Drain Trap Replacement Replace the Drain trap following the procedures below. 1. Disconnect electrical power to the unit. 2. Drain water from the Drain trap using the drain valve located underneath the water heater (Fig.). 3. Disconnect the relay connector(2 positions), remove the fixing screw, and remove drain hose 1 and drain hose 2. (Fig.). Remove the Drain trap by lifting up on it to disengage the tabs.
Fan Motor Replacement When changing the fan motor. When Bell-mouth(B) is installed in the old fan motor, install Bell-mouth (B) as shown in figure to maintain the proper air volume. When you change the fan motor, please remove this part from the old fan motor, and install in the new fan motor. After changing the fan motor, please follow the procedure "Circuit Board Settings ". The water heater will not operate properly unless you carry out this step.
Anti Frost Heater Replacement Attention in after-sale service Please check the original position and re-install to this position. The anti-frost heater shall be installed with the method described in the diagram below. Heater position (Adjust the edges) Adjust the heater and the heater fastener. Push the heater fastener all the way to the right side of the heat exchanger described in the diagram.
Manifold Gas Pressure Adjustment NOTE: * Use the following procedure to adjust the manifold gas pressure only if it can be done with a high flow rate through the unit. (1) With a manometer or pressure gauge connected to the manifold pressure tap, press and hold the maximum pressure set button. Use the manifold pressure increase and decrease buttons to adjust to the correct pressure. (2) Press and hold the minimum pressure set button.
Maintenance (1) Troubleshooting and Repair. A. Unit does not work at all (operation lamp does not light up). 1. Is the current leakage safety device activated? Check the operation of the current leakage safety device. (1) When the ground-fault lamp of the current leakage safety device lights, press the reset button or disconnected power plug to cancel. If the current leakage safety device cannot be canceled, check for electric leakage around power receptacle, etc.
4. Blown current fuse. Check for blown current fuse on the circuit board. (1) Remove the power plug (current leakage safety device). (2) Visually check the current fuse (10A) on the circuit board to see if it is blown. Normal Not blown Yes Continue to “5. Remote control error”. No Replace the current fuse (10A). If the fuse blows again, check for short circuits. 5. Remote control error. Check the voltage of the remote control terminal block. (1) Measure the voltage of the terminal block.
7. Error display 14 immediately after turning unit ON. Inspect overheat prevention device (thermal fuse). (1) Remove connector 38 on the circuit board and measure the resistance between Blue 25 and Blue 31. Normal Yes No 2Ω or less Replace the circuit board. After finding cause of overheating, replace the thermal fuse. 8. Error display 90 or 99 immediately after turning Inspect the usage status of the unit. unit ON. • If error display 99, then end of service life: replace the unit.
(2) Measure the voltage between Red 1 and Blue 7 of connector 75 on the circuit board. Normal DC 14 - 16V Yes Replace the water flow sensor. No Replace the circuit board. 2. Error display 20 immediately after turning unit Inspect the high-limit switch. ON. (1) Remove connector 1 and connector 92 on the circuit board and measure the resistance between Black 3 of connector 1 and White 6 of connector 1. Normal Yes No 3. Water inlet thermistor error. 1Ω or less Replace the circuit board.
4. Water outlet thermistor error. If error display 32 appears, then check the water outlet thermistor. (1) Measure the resistance between White 1 and White 2 of connector M64. Break in wire: ∞Ω Short circuit: 1Ω or less If wire is broken or short-circuited, replace the water outlet thermistor. If the problem is not a broken or short-circuited wire, then inspect/repair the wirings/connectors of the water outlet thermistor. 5. Heat exchanger thermistor error.
7. Gas solenoid valve error. If error display 11 appears and there is continuous electrical discharge, then check the gas solenoid valves. (1) Open the hot-water supply valve and measure the voltages between: SV0: White 6 and Blue 7 on connector 10 SV1: Black 5 and Blue 7 on connector 10. Normal 8. Fan motor error. DC 80 - 100V Yes Replace the bad gas solenoid valve. No Replace the circuit board. If error display 61 appears, then check the fan motor.
10. Flame rod error. If error display 12 or 72 appears, then check the flame rod. (1) Measure the frequency between the flame rod and burner case (GUD) when the remote controller is turned on. Normal 10kHz - 100kHz Yes Continue to (2). No Replace the circuit board. (2) Measure the current between flame rod (or Blue 1 of connector 78) and electrode. 11. Drain trap water level electrode error.
(2) Measure the voltage between Blue 29 of connector 38 and Red 9 of connector 63 on the circuit board. Normal Yes DC 4V or more Replace the circuit board. • Check the clogging of drain piping, No drain trap and connection hose. • Replace the circuit board. C. Hot-water supply temperature cannot be adjusted. 1. Water inlet thermistor error. Check the water inlet thermistor. • Check to see whether the actual water temperature and displayed data of maintenance information monitor no. 30 match.
Check the heat exchanger thermistor. 3. Heat exchanger thermistor error. • Check to see if the displayed data of maintenance information monitor no. 32 and no. 42 match. (1) Measure the resistance between White 1 and White 4 of connector Q64. Temp.(°C) Normal 10 20 30 40 50 60 70 80 Resistance(kΩ) 23.7 15.5 10.3 7.0 4.9 3.5 2.5 1.9 1.4 Yes No 4. Gas solenoid valve error. 0 Check “4. Gas solenoid...” and “6. Bypass flow control...”. Replace the heat exchanger thermistor.
5. Gas proportioning valve error. Check the gas proportioning valve error. (1) Check to see if the flame size changes when pressing the minimum and maximum manifold pressure set button, then measure the voltage between Red 2 and Blue 4 using connector 38 on the circuit board. Normal Yes No 6. Bypass flow control valve error. DC 0.3 - 15V Continue to “6. Bypass flow...”. Change the gas proportioning valve. Replace the circuit board. Check the bypass flow control valve.
(2) Disassembly of each part 1. How to remove transformers (1) Remove two quick fasteners (A and B) in the right figure and remove the water inlet pipe (C). B C A (2) Remove the quick fastener (A) in the right figure and pull the bypass servo (B). A B (3) Unscrew two fixing screws (A and B) in the right figure and remove the transformers.
2. How to remove the board (1) Unscrew two screws (A and B) that fix the board and the earth screw (C) and remove the board. A C B 3. How to remove the manifold - Unscrew two fixing screws of mounting plate for current leakage safety device in advance. (1) Remove the quick fastener (A) in the right figure and slide the gas pipe (B) upward. B A (2) Unscrew four screws that fix the manifold and pull out the manifold SET.
Installation Filling the drain trap unit with water The drain trap unit can be filled before connecting the vent pipe. Filling the drain trap unit before vent pipe installation. DANGER Prior to initial start up, make sure that you fill the drain trap unit with water. This is to prevent dangerous exhaust gases from entering the building. Failure to fill the drain trap unit could result in severe personal injury or death.
Specifications Item Specification Model Name Type WHC56 Installation Internal, Wall Mounted Air Supply/Exhaust Power Vented Ignition Direct Ignition 2.0 bar Minimum Pressure for Maximum flow 2.5 L/min. Minimum Flow Rate 61.5 cm(Height) x 46.4 cm(Width) x 24 cm(Depth) Dimensions Weight 33 kg Water Holding Capacity Connection Sizes Power Supply Materials 1.
Dimensions WHC56 < mm > 450 4- 13 6-6 x 10 OBLONG HOLE 100.8 (OUTER) 10 40 36 EXHAUST PIPE CONNECTION 464 AIR INLET 150 78 240 130 232 101.
Baxi Commercial Division Wood Lane, Erdington, Birmingham B24 9QP Email: andrews@baxigroup.com www.andrewswaterheaters.co.
